Mercurial > sdl-ios-xcode
diff src/audio/SDL_audiomem.c @ 0:74212992fb08
Initial revision
author | Sam Lantinga <slouken@lokigames.com> |
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date | Thu, 26 Apr 2001 16:45:43 +0000 |
parents | |
children | cf2af46e9e2a |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/audio/SDL_audiomem.c Thu Apr 26 16:45:43 2001 +0000 @@ -0,0 +1,73 @@ +/* + SDL - Simple DirectMedia Layer + Copyright (C) 1997, 1998, 1999, 2000, 2001 Sam Lantinga + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public + License as published by the Free Software Foundation; either + version 2 of the License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with this library; if not, write to the Free + Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + + Sam Lantinga + slouken@devolution.com +*/ + +#ifdef SAVE_RCSID +static char rcsid = + "@(#) $Id$"; +#endif + +/* Functions to allocate audio buffer memory, shareable across threads + (necessary because SDL audio emulates threads with fork() + */ + +#ifdef FORK_HACK +#include <sys/types.h> +#include <sys/ipc.h> +#include <sys/shm.h> +#include <stddef.h> +#else +#include <stdlib.h> +#endif + +#include "SDL_audiomem.h" + +/* Allocate memory that will be shared between threads (freed on exit) */ +void *SDL_AllocAudioMem(int size) +{ + void *chunk; + +#ifdef FORK_HACK + int semid; + + /* Create and get the address of a shared memory segment */ + semid = shmget(IPC_PRIVATE, size, (IPC_CREAT|0600)); + if ( semid < 0 ) { + return(NULL); + } + chunk = shmat(semid, NULL, 0); + + /* Set the segment for deletion when it is detatched */ + shmctl(semid, IPC_RMID, NULL); /* Delets semid if shmat() fails */ +#else + chunk = malloc(size); +#endif + return((void *)chunk); +} + +void SDL_FreeAudioMem(void *chunk) +{ +#ifdef FORK_HACK + shmdt(chunk); +#else + free(chunk); +#endif +}